Several Japanese record companies are being investigated by the Japanese government's Fair Trade Commission on suspicion of antitrust violations.

TOKYO -- Several Japanese record companies are being investigated by the Japanese government's Fair Trade Commission on suspicion of antitrust violations.

The commission searched the offices of several record companies on Aug. 26 in connection with alleged refusals to allow other companies to use their repertoire for mobile-phone ringtunes, which are derived from master recordings.

Among the companies whose offices were raided were the local affiliates of the major international labels, as well as local independents such as Avex and Victor Entertainment.

Also searched were the offices of Label Mobile, a Tokyo-based ringtones/tunes provider that is jointly owned by Avex Network (an Avex subsidiary), Sony Music Entertainment (Japan), Victor Entertainment, Toshiba-EMI and Universal Music K.K. Twelve other Japanese labels sell ringtunes through Label Mobile.

Although there are about 100 ringtune distribution companies in Japan, Label Mobile has an estimated 80% share of the 10 billion yen ($90.8 million) Japanese ringtune market.

At deadline, it was unclear whether any charges would be pressed in connection with the raids.